Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael...
[linux-2.6.git] / net / netfilter / xt_CT.c
1 /*
2  * Copyright (c) 2010 Patrick McHardy <kaber@trash.net>
3  *
4  * This program is free software; you can redistribute it and/or modify
5  * it under the terms of the GNU General Public License version 2 as
6  * published by the Free Software Foundation.
7  */
8
9 #include <linux/module.h>
10 #include <linux/gfp.h>
11 #include <linux/skbuff.h>
12 #include <linux/netfilter_ipv4/ip_tables.h>
13 #include <linux/netfilter_ipv6/ip6_tables.h>
14 #include <linux/netfilter/x_tables.h>
15 #include <linux/netfilter/xt_CT.h>
16 #include <net/netfilter/nf_conntrack.h>
17 #include <net/netfilter/nf_conntrack_helper.h>
18 #include <net/netfilter/nf_conntrack_ecache.h>
19 #include <net/netfilter/nf_conntrack_zones.h>
20
21 static unsigned int xt_ct_target(struct sk_buff *skb,
22                                  const struct xt_action_param *par)
23 {
24         const struct xt_ct_target_info *info = par->targinfo;
25         struct nf_conn *ct = info->ct;
26
27         /* Previously seen (loopback)? Ignore. */
28         if (skb->nfct != NULL)
29                 return XT_CONTINUE;
30
31         atomic_inc(&ct->ct_general.use);
32         skb->nfct = &ct->ct_general;
33         skb->nfctinfo = IP_CT_NEW;
34
35         return XT_CONTINUE;
36 }
37
38 static u8 xt_ct_find_proto(const struct xt_tgchk_param *par)
39 {
40         if (par->family == NFPROTO_IPV4) {
41                 const struct ipt_entry *e = par->entryinfo;
42
43                 if (e->ip.invflags & IPT_INV_PROTO)
44                         return 0;
45                 return e->ip.proto;
46         } else if (par->family == NFPROTO_IPV6) {
47                 const struct ip6t_entry *e = par->entryinfo;
48
49                 if (e->ipv6.invflags & IP6T_INV_PROTO)
50                         return 0;
51                 return e->ipv6.proto;
52         } else
53                 return 0;
54 }
55
56 static int xt_ct_tg_check(const struct xt_tgchk_param *par)
57 {
58         struct xt_ct_target_info *info = par->targinfo;
59         struct nf_conntrack_tuple t;
60         struct nf_conn_help *help;
61         struct nf_conn *ct;
62         int ret = 0;
63         u8 proto;
64
65         if (info->flags & ~XT_CT_NOTRACK)
66                 return -EINVAL;
67
68         if (info->flags & XT_CT_NOTRACK) {
69                 ct = nf_ct_untracked_get();
70                 atomic_inc(&ct->ct_general.use);
71                 goto out;
72         }
73
74 #ifndef CONFIG_NF_CONNTRACK_ZONES
75         if (info->zone)
76                 goto err1;
77 #endif
78
79         ret = nf_ct_l3proto_try_module_get(par->family);
80         if (ret < 0)
81                 goto err1;
82
83         memset(&t, 0, sizeof(t));
84         ct = nf_conntrack_alloc(par->net, info->zone, &t, &t, GFP_KERNEL);
85         ret = PTR_ERR(ct);
86         if (IS_ERR(ct))
87                 goto err2;
88
89         ret = 0;
90         if ((info->ct_events || info->exp_events) &&
91             !nf_ct_ecache_ext_add(ct, info->ct_events, info->exp_events,
92                                   GFP_KERNEL))
93                 goto err3;
94
95         if (info->helper[0]) {
96                 ret = -ENOENT;
97                 proto = xt_ct_find_proto(par);
98                 if (!proto)
99                         goto err3;
100
101                 ret = -ENOMEM;
102                 help = nf_ct_helper_ext_add(ct, GFP_KERNEL);
103                 if (help == NULL)
104                         goto err3;
105
106                 ret = -ENOENT;
107                 help->helper = nf_conntrack_helper_try_module_get(info->helper,
108                                                                   par->family,
109                                                                   proto);
110                 if (help->helper == NULL)
111                         goto err3;
112         }
113
114         __set_bit(IPS_TEMPLATE_BIT, &ct->status);
115         __set_bit(IPS_CONFIRMED_BIT, &ct->status);
116 out:
117         info->ct = ct;
118         return 0;
119
120 err3:
121         nf_conntrack_free(ct);
122 err2:
123         nf_ct_l3proto_module_put(par->family);
124 err1:
125         return ret;
126 }
127
128 static void xt_ct_tg_destroy(const struct xt_tgdtor_param *par)
129 {
130         struct xt_ct_target_info *info = par->targinfo;
131         struct nf_conn *ct = info->ct;
132         struct nf_conn_help *help;
133
134         if (!nf_ct_is_untracked(ct)) {
135                 help = nfct_help(ct);
136                 if (help)
137                         module_put(help->helper->me);
138
139                 nf_ct_l3proto_module_put(par->family);
140         }
141         nf_ct_put(info->ct);
142 }
143
144 static struct xt_target xt_ct_tg __read_mostly = {
145         .name           = "CT",
146         .family         = NFPROTO_UNSPEC,
147         .targetsize     = sizeof(struct xt_ct_target_info),
148         .checkentry     = xt_ct_tg_check,
149         .destroy        = xt_ct_tg_destroy,
150         .target         = xt_ct_target,
151         .table          = "raw",
152         .me             = THIS_MODULE,
153 };
154
155 static int __init xt_ct_tg_init(void)
156 {
157         return xt_register_target(&xt_ct_tg);
158 }
159
160 static void __exit xt_ct_tg_exit(void)
161 {
162         xt_unregister_target(&xt_ct_tg);
163 }
164
165 module_init(xt_ct_tg_init);
166 module_exit(xt_ct_tg_exit);
167
168 MODULE_LICENSE("GPL");
169 MODULE_DESCRIPTION("Xtables: connection tracking target");
170 MODULE_ALIAS("ipt_CT");
171 MODULE_ALIAS("ip6t_CT");